This is a large vintage glass lamp shade, probably early 1900's and very possibly a Hobs. The dots nearer the bottom are elongated, where as the ones up top and much more pointed. It is ruby red and has a hobnail type dot pattern. It measures 14" and has a 5 3/8" opening.
It is in perfect condition. This came from the estate of a well known high end lamp collector. All her stuff was top of the line. This shade is no exception.
I will be listing dozens of lamps and shades as well as thousands of lamp parts, so check my other listings.